Manufacture of artificial-silk threads from cellulose.



ERNST BECHTEIl, OF HANAU, GERMANY, ASSIGNOR TO HANAUER KUNSTSEILDEFABRIK AGTIENGESELLSCHAFT, OF GROSS-,AUHEIM, NEAR HANAU, GERMANY, A CORIOIR-A- TIOIN OF GERMANY MANUFACTURE OF ARTIFICIAL-SILK THREADS FROM CELLULOSE.

No Drawing.

To all whom it may concern:

Be it known that'I, ERNST BECIITEL, a subject of the Emperor of Germany, and resident of I-Ianau-on-the-Main, Germany, have invented certain new and useful Improvements in the Manufacture of Art-i- -ficial-Silk Threads from Cellulose; of which the following is a specification.

This invention relates to improvements in the process for the manufacture and production of artificial silk threads from cellulose dissolved in ammoniac'al eupric oxid,

alkali caustic lye being employed as the precipitant. V

It has been generally supposed .that perfect threads of artificial silk of marketable value could only be obtained from cellulose dissolved in ammoniaeal cupric oxid by means of alkali lye as precipitating liquor when the alkali lye was heated. I have now discovered that'it is not necessary to heat the alkali lye for the production of perfectly fine silk threads,,if the solution of cellulose in ammoniacal cupr ic oxid to be spun; be heated before it enters the setting bath, and the coagulation be carried out in this heated state. This new discovery is accounted for by the fact that a perfect precipitation of cellulose solutions with alkali lye depends essentially and solely on the ammonia contained in the solution being so liberated that it can readily escape from the solution, whether this solution issuesout in warm or cold soda lye. The result, as before stated,

has already been partly attained if'hot lye be used, since the latter loosens the combination of the solution with the ammonia.

The heating of the solution of cellulose in the ammoniacal cupfie oxid before entering the lye according to the present invention, which lye maybe cold, has the great advantage over the employment of hot lye,

that the heating can be effected in a very Specification of Letters Patent. Applicatibn filed August 14, 1912. 7 Serial No. 715,117.

Patented July 8, 1913.

simple and uniform manner, whereas heatmg in the case of most precipitating liquors has never been carried out hitherto with the complete uniformity requisite for obtaining a perfectly uniform final product.

For the purpose of the preliminary heating the solution, before entering the setting bat is passed along in contact with a constant supply of heat, which" may be either steam, heated air' or any other regulated source of heat. Still better results are obtained when the solution is previously heated and is allowed to enter the lye which.

is alsoheated since in the latter case the dis sociation of the solution is effected with greater rapidity and in consequence the speed of withdrawal of the spun thread can be considerably increased. If this double heating be employed the speed of with drawal can be increased up to from 70 to 0 nietersper minute.

What I claim is- 1. In the'manufacture of threads of artificial silk from cellulose dissolved in ammoniacal cupric oxid, causticalkali lye being used as the precipitant, the step of heating the solution of cellulose before its -entrance into the setting bath.

2. In the manufacture of threads of artificial silk from cellulose dissolved in ammoniacal cupric oxid caustie alkali lye being used' as the precipitant, the step of heating the solution of cellulose as Well as the settin bath into which the heated solution of co lulose is introduced.

In testimony whereof I have signedmy name to this specification in the presence of two subscribing witnesses.

ERNST BECHTEL.

Witnesses:

FRANZ HAssLAoHEn, Josnr Wnsrnorrn. 

